<style>
    .text {
        border-bottom: 1px solid #ccc;
    }

    .text-baseline {
        vertical-align: baseline;
    }

    .text-top {
        vertical-align: top;
    }

    .text-middle {
        vertical-align: middle;
    }

    .text-bottom {
        vertical-align: bottom;
    }
</style>
<div>
    <span class="text text-baseline">绝知此事要躬行</span>
    <span class="text text-top">绝知此事要躬行</span>
    <span class="text text-middle">绝知此事要躬行</span>
    <span class="text text-bottom">绝知此事要躬行</span>
</div>